Unplanned dredging done by the government in the name of maintaining the rivers' navigability is actually destroying the rivers, alleged environmental experts at a webinar.
They also opined that sand mining in the country is also done in an unplanned way, which only profits the influential political figures and corruption is involved in this process too.
Environmentalists made the comments at a webinar titled "River Sand Mining and Navigation Management: Costs and Benefits," jointly organised by the Change Initiative and Oxfam Bangladesh on Thursday.
"Unplanned sand mining or dredging changes the flow of current which increases river erosion," said Dr M Inamul Haq, chairman of Institute of Water and Environment, while presenting the keynote paper at the event.
"A proper hydrographic study should be conducted before declaring a place as 'balumahal' (an area from where sand is lifted) or start dredging," he recommended.
Mokhlesur Rahman, a social worker from Chandpur, said there are six balumahals in the district.
"Influential people have taken lease of those balumahals, and they were illegally lifting sand from spots near the shore. This has increased river erosion and has already affected 3,700 families in one union," said Mokhlesur.
He further said lifting sand continuously also destroys the eggs of hilsa fish – an issue which is not addressed by any organisation.
Syed Monowar Hossain, consultant of Institute of Water Modelling, said there are rules that before starting sand mining in an area, a hydrography team from Bangladesh Inland Water Transport Authority has to inspect and conduct a pre-study. But the rule is rarely followed.
Attending the programme as the chief guest, Secretary of Shipping Ministry Mohammad Mezbah Uddin Chowdhury assured the people concerned of addressing all these irregularities.
"Around 16% people in the country use waterways and we are trying to raise the number. Maintaining navigability of 178 rivers across the country, we are trying to improve the dredging management system," said the secretary.
"We have addressed the issue of irregularities in sand mining in a cabinet meeting and already surveyed seven balumahals," he said adding that the rest of the balumahals will also be surveyed.